A procedure for the analysis by mass spectrometry of the structure of oligosaccharides from high-mannose glycoproteins

Abstract

A strategy, based on mass spectrometry, for analysis of the structure of oligosaccharides obtained from high-mannose glycoproteins, is described. The oligosaccharides are analysed first by f.a.b.-m.s. as the acetylated alditols, then O-deacetylated, oxidised with periodate, and reduced with borodeuteride. The products are analysed further by f.a.b.-m.s. after acetylation and subsequently by both f.a.b.- and e.i.-m.s. after methylation. The entire procedure is carried out on the same sample and the data allow assignment of the positions of all of the glycosidic linkages, including those of the branched residues. Individual components in mixtures of isomeric compounds can often be identified from f.a.b.-m.s. by their molecular weights after periodate oxidation.